screen buzz when brightness isn't set to max, what can I do?

[jhonyl]

Hi,

I have noticed that my screen buzz, when I am on battery power, what can I do? When I plug the AC the buzz stops.

Edit: I have found out that on AC it doesn't buzz only if the brightness is set to maximum. When the brightness is lower it buzz on AC too. On battery the maximum brightness isn't the "real" maximum so it always buzz.

[dsigma6]

I don't think there's much you can do about it, unless the inverter causes the noise.

I've had a few older machines that made the same noise, but I couldn't nitpick on second-hand goods.

[GomJabbar]

You can change the LCD brightness setting in ThinkPad Configuration or the BIOS from Normal to High. Note that this setting is different than the screen brightness settings available from Fn + Home & Fn + End. EDIT: Or from Battery Maximizer or Windows Power Options.

When the LCD brightness setting is at Normal, the display dims when on battery power. When the LCD brightness setting is at High, the screen does not dim when on battery power (well it does dim slightly because of less voltage available). These settings have no effect on AC power display brightness.

EDIT: To clarify --- Your power management settings can still dim the display when on battery if that is the way you have it set up. For the above, I was meaning that you would already have chosen the same display brightness settings for battery and AC in Battery Maximizer or Windows Power Options.

[jhonyl]

Hi,

I don't want to use max brightness all the time. I have seen somewhere on the net' someone that has recommend to take the screen apart, and fixate everything there better, since the buzz he said is from some loose component. I would like to do that, but I am a bit scared because I am not sure if I could put it back together ok, and if it would look like I have screwed with it.

[JohnnyM]

There's nothing loose in your screen, it's the inverter board that's causing the whine and it's normal. Some inverters buzz or whine louder than others. For a truly technical answer, an electrical engineer will have to step in here...

[rkawakami]

For a truly technical answer, an electrical engineer will have to step in here...

I aren't (sic) one, but I agree with JohnnyM . The inverter is probably the source of the buzzing. Think of it as something similar to an electrical transformer. The inverter is designed to convert a small DC voltage into a large AC voltage. On the inverter to a T23 there's two coils (transformers) that are being used. A picture of one for the T4x shows only one, but it's a large one. The inverter is designed to oscillate at a high frequency. If the coil windings are loose, that oscillation can cause the audible noise (buzz or whine) that you hear. If it is really annoying, I would try replacing the inverter. They can be had for cheap ($10-$20) on eBay and are pretty easy to change.